Variable Circulation Rate Sub for Delivering a Predetermined Straight through Flow

ABSTRACT

A housing is integrated into a tubing string having a straight through passage and a lateral wall exist. Inside the passage is a flow responsive member with an applied preload force. Flow corresponding to a predetermined differential pressure in the housing will not move the valve member so all flow will go straight through in a downhole direction. As flow increases, the preload bias is overcome to align the passage through the housing and openings in the valve member with wall openings. As flow into the housing increases, more lateral wall opening area is aligned with the passage to increase circulation flow while holding through flow downhole constant. Dropping a ball on the valve member blocks through flow and allows opening of total bypass passages. The ball can be removed by blowing it through the seat or otherwise failing or disintegrating it.

FIELD OF THE INVENTION

The field of the invention is downhole circulation subs and more particularly subs that vary circulation rate to hold a predetermined straight through flow responsive to incoming flow and with a capability to be selectively placed in full recirculation or automatic recirculation modes.

BACKGROUND OF THE INVENTION

In drilling operations it is sometimes necessary to deliver a predictable flow rate to a mud motor, directional drilling equipment or the bit. Automatic systems have been developed to accomplish this task but they are complex and very expensive to install and operate. One example of such a system that sequentially opens and closes surface mounted choke valves is described in WO2015/179408 beginning at paragraph 53. Systems with similar complexity are described in U.S. Pat. No. 7,353,887. On the other hand, very basic systems that detect fluid loss during drilling and which rely on differential pressure measurements are revealed in U.S. Pat. No. 3,595,075. Systems that respond to fluid physical properties are described in U.S. Pat. No. 9,260,952.

More relevant to the desired simplicity of the present invention is U.S. Pat. No. 9,145,748 FIGS. 1A and 1B where a flow activated device has two modes of flow straight through and total flow recirculation. The device of the present invention allows total flow straight through below a predetermined amount and then progressively recirculates any excess as input flow rate increases. Another mode is full recirculation by dropping a ball on a seat and selectively overcoming the flow responsive circulation mode by blocking the main flow passage and sending all incoming fluid laterally through a wall port for recirculation. The total recirculation mode can then be overcome by either blowing a seated ball through a seat or otherwise weakening or disintegrating the ball. Normal drilling can resume as the flow through the string is reinstated to the desired flow rate, above which recirculation begins again. These and other aspects of the present invention will become more readily apparent to those skilled in the art from a review of the detailed description of the preferred embodiment and the associated drawings while recognizing that the full scope of the invention is to be determined by the appended claims.

SUMMARY OF THE INVENTION

A housing is integrated into a tubing string having a straight through passage and a lateral wall. Inside the passage is a flow responsive member with a preload force applied to it. Flow corresponding to a predetermined pressure difference in the housing will not move the valve member, so all flow will go straight through in a downhole direction. As flow increases, the preload bias is overcome to align the passage through the housing and openings in the valve member with wall openings. As flow into the housing increases, more lateral wall opening area is aligned with the passage to increase circulation flow while holding through flow downhole constant. Dropping a ball on the valve member blocks through flow and allows opening of total bypass passages. The ball can be removed by blowing it through the seat or otherwise failing or disintegrating it.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a section view of the device in a position where all flow runs through the housing axially;

FIG. 2 is the view of FIG. 1 where flow has increased beyond a predetermined amount and some recirculation takes place with the through flow rate holding steady;

FIG. 3 is the view of FIG. 2 with a ball dropped on the valve member blocking straight through flow and enabling all flow to recirculate.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1, a housing 10 with an uphole connection 12 to a tubular string that is not shown. A downhole end 14 can be connected to a bottom hole assembly for drilling that is also not shown. For a number of reasons, the bottom hole assembly that is not shown needs a predetermined flow rate out the downhole end 14. Flow coming into uphole end 12 enters passage 16 where a valve member 18 is located that has flow path 20 therethrough that aligns with passage 16. Housing 10 has an internal shoulder 22 that acts as an uphole travel stop for the valve member 18 under the bias of a stored force. In this case, the preferred mode for the force is a coiled spring 24. Sleeve 26 schematically illustrates a device that can be used to change the preload on spring 24 which has the effect of changing the amount of flow coming into uphole end 12 that will go straight through to downhole end 14 without being circulated through openings 28, 30 or 32. In the FIG. 1 position openings 28 and 30 are blocked by seals 34 and 36 straddling them, while ports 32 are blocked by seals 38 and 40. Valve member 18 has an opening 42 between seals 34 and 40. In FIG. 1, opening 42 is effectively closed against the housing 10 due to the position of seals 40 and 34. Wall ports 28 and 30 are used for recycle flow beyond a predetermined amount headed to the bottom hole assembly. Openings 32 are for full recycle when no flow goes to the bottom hole assembly and ports 28 and 30 are preferably blocked. During such times, a blocker can be pumped into the formation without having to pass through smaller control openings 28 and 30 which can be needed later when flow to the bottom hole assembly again needs to be controlled and the full recycle ports 32 are closed, as will be described below.

The position of the components in FIG. 1 is held until a predetermined flow into uphole end 12 exerts enough force on valve member 18 to begin movement of valve member 18 against the spring 24 as the spring compresses. Seal 34 is pushed downhole past openings 28 so that some circulation flow can start out openings 28 while straight through flow remains unchanged. For example, if the target straight through flow is 10 barrels per minute (BPM) and the input flow is increased to 15 BPM, the result will be 5 BPM passing through ports 28 and 10 BPM continuing straight through to the bottom hole assembly. If the input flow is picked up to say 20 BPM, the valve member would move further to the right and increase the effective annular flow area through the ports. An increase in flow beyond the valve's designed range will cause shorter and stiffer spring 46 to engage the valve member and effectively stop its movement to the right. Those skilled in the art will appreciate that the above described device can be mathematically modeled taking into account the quantity and geometry of the openings, the strength of spring 24, and the amount of applied preload to ensure that a predetermined amount will flow axially to the bottom hole assembly and that when the incoming flow exceeds that predetermined amount, the valve member 18 movement and sequential opening of lateral ports in the housing 10 to circulation flow will maintain the flow to the bottom hole assembly at the desired predetermined level.

When used in a drilling assembly and the formation begins to take on fluids, there would be a reason to stop drilling and use the drill string with the housing 10 to deliver seal material in significant quantities to the formation. In that case, a ball 48 is landed on seat 50 and pressure is applied to shift the valve member 18 far enough past openings 32 to redirect all flow with the sealing material to the formation through openings 32. Openings 32 can be plugged with balls 52 after the pumping of the sealing material is concluded to increase the pressure high enough to blow ball 50 and right after it balls 52. A ball catcher that is not shown can collect the balls 50 and 52 in a capture volume that surrounds the main flow passage that is the continuation of passage 16. In that case, the FIG. 1 position is regained and drilling can resume. The opening of passages 32 and their subsequent closing with balls 52 and the capture of balls 50 and 52 in a ball catcher is described in a co-pending application filed on Nov. 2, 2016 and having Ser. No. 15/341,180.

It should be noted that the number of openings and their spacing and the number of rows can be varied depending on the desired control accuracy desired for control of through flow and the control of the variable recirculation rate. Spring 46 can be optionally replaced by a shoulder in housing 10 that selectively engages the valve member 18 after a finite movement. Spring 24 can be a coiled spring, a stack of Belleville washers or a pressure chamber holing a compressible gas. Ports 28 and 30 instead of being discrete rows of ports can be presented in the form of axial slots that get progressively wider. Ports 32 can also be integrated into the widening axial slot arrangement for the lateral exit openings. Since the lateral ports can be closed even after dropping the balls as in FIG. 3 the integrity of the string to conduct pressure is maintained so that a pressure test can be run or drilling resumed after the conclusion of the lateral pumping of sealant material out ports 32.

The above description is illustrative of the preferred embodiment and many modifications may be made by those skilled in the art without departing from the invention whose scope is to be determined from the literal and equivalent scope of the claims below: 

We claim:
 1. A flow regulation device to a bottom hole assembly supported on a tubular string in a wellbore, comprising: a housing comprising a through passage and at least one lateral wall opening communicating with said passage; a valve member biased in said passage by a first bias having a flow path therethrough directing up to a predetermined flow entering said housing to said bottom hole assembly, said valve member maintaining said predetermined flow to said bottom hole assembly in response to increases in flow to said housing above said predetermined flow by movement of said valve member against said bias to selectively open said at least one lateral wall opening to divert flow from said housing that in excess of said predetermined flow away from said bottom hole assembly.
 2. The device of claim 1, wherein: said first bias comprises at least one of a coiled spring, Belleville washers and a compressible fluid.
 3. The device of claim 1, wherein: said at least one lateral wall opening comprises a plurality of lateral wall openings arranged in axially spaced rows, wherein movement of said valve member against said first bias opens at least one of said rows.
 4. The device of claim 1, wherein: said valve member is movable into a configuration where no flow is directed to the bottom hole assembly by blocking said flow path in said valve member with a first object and shifting said valve member with said first object to selectively open at least one full recycle port in said housing.
 5. The device of claim 4, wherein: said at least one lateral wall opening is closed by said valve member when said at least one full recycle port is open.
 6. The device of claim 5, wherein: said at least one full recycle port is selectively closed by at least one second object thereby allowing pressure buildup on said first object to force said first and second objects through said flow path to enable said first bias to close said at least one full recycle port for resumption of said predetermined flow to the bottom hole assembly.
 7. The device of claim 1, wherein: said predetermined flow is adjustable with a preload applied to said first bias on said valve member.
 8. The device of claim 3, wherein: a second bias engages said valve member after all said axially spaced rows of said lateral wall openings are open.
 9. The device of claim 8, wherein: said second bias is stronger than said first bias.
 10. The device of claim 1, wherein: said at least one lateral wall opening comprises a plurality of circumferentially spaced axially elongated tapered lateral wall openings.
 11. The device of claim 10, wherein: said valve member is movable into a configuration where no flow is directed to the bottom hole assembly by blocking said flow path in said valve member with a first object and shifting said valve member with said first object to selectively open at least one full recycle port in said housing.
 12. The device of claim 11, wherein: said at least one full recycle port comprises a plurality of full recycle ports axially aligned with said tapered lateral wall openings.
 13. The device of claim 12, wherein: said recycle ports and tapered lateral wall openings are integrated into a continuous port.
 14. The device of claim 1, wherein: said valve member holding housing pressure in said passage at flow rates below said predetermined flow. 